FORM 2
THE PATENTS ACT1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13) TITLE OF THE INVENTION
A Regeneration System for Particulate Filter
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Dattatraya R. Katkar, Mr. Deepak S. Kulkarni, Mr. Nilesh A Lende
All Indian nationals
of TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
This invention relates to a regeneration system for particulate filter more particularly to diese! particulate filters. More particularly, the invention refers to external regeneration arrangement for diesel open particulate filters.
BACKGROUND OF THE INVENTION:
Stricter regulatory emissions norms coupled with rising customer expectations are two primary driving forces for development in automotive industry. In addition market driven forces like cost of ownership and competition also pose challenges to automotive manufacturer. Control over oxides of nitrogen and particulate matter are two critical requirements for diesel engines. These conflicting requirements can be addressed with following options -
i) Refinement at engine / vehicle level
ii) Technological upgrade
iii) Use of innovative technologies
Diesel particulate trap is one of the cost effective solutions to address these requirements. The functioning of diesel particulate trap depends on storing the engine out particulate matter and at a later time burning the same through catalytic regeneration process. The diesel particulate trap system works satisfactorily if the particulate storage and regeneration are balanced. At present the regeneration depends primarily on passive regeneration which is dependent on engine / vehicle configuration and calibration. This balance may get disturbed during prolonged low speed, part load operation. This puts a limitation on use of diesel particulate trap for diesel engines. Thus, if any external mechanism is provided to assist for the regeneration of diesel particulate trap, it will improve its reliability. The present invention aims at providing an external system & arrangement for improving the regeneration performance of the diesel particulate trap.
Considerable amount of development work has been carried out on regeneration of the diesel particulate trap.
One prior art teaches about an apparatus & a process for clogged solid particle filters, particularly for diesel engines. There is a periodically injected upstream from the clogged

filter an organic liquid such as CxHyOz, of the ethyl methyl alcohol type., having low vapourisation temperature, if necessary with water added. The organic liquid, after having been preheated and cracked to give rise to a very flammable mixture consisting essentially of hydrogen & carbon monoxide, is introduced in the path of incident exhaust gases. The regeneration apparatus comprises of two prechambers, each of which contains a glow plug. The burning of the flammable mixture regenerates the clogged filter.
Another Prior Art teaches a system and related method for cleaning a particulate filter medium. The filter medium is cleaned by the input of energy to burn off particulate matter collected thereon. The system can comprise a thermocouple for monitoring the temperature of the medium at plurality locations. There is an electronic control unit for determining the point having a maximum individual temperature & creating a control commensurate with the maximum temperature. The control unit can determine if the control signal exceeds a predetermined set point level & if so reduces the energy input. The control unit also determines if the control signal falls within a predetermined range, also referred to as a band width of acceptable values less than the set point level. If the signal falls within the band width, the controls unit controls the energy input & varies it as appropriate in order to maintain the control signal within the band width.
Yet another prior art teaches about a filter system, a regeneration system, a combined regeneration system & applications for the systems. The filter system may act as a purifier & a muffler for heavy 8c light duty diesel vehicles. The invention is unique dual pass filter that removes particulates & nitrogen oxides in successive passes before the gas exits the filter. The regeneration system includes an electric-powered heat source for safety & better control of the regeneration process. A motor vehicle application is also disclosed. The first prior art uses an organic liquid as a source of heat. The second patent deals with the temperature control aspect of the regeneration by monitoring the temperature of the surface of the particulate trap. The third invention is about dual pass filter that removes particulates & nitrogen oxides in successive passes before the gas exits the filter.
All these prior arts provide heat to initiate the regeneration process. However, none of the prior arts deal with fresh air as a necessary element.

OBJECT OF THIS INVENTION:
The main object of the present invention is to obviate above mentioned drawbacks.
Another object of the invention is to provide an external regeneration arrangement for diesel particulate trap.
Yet another object of the present invention is to provide an external arrangement for regeneration of the POC that is independent of the operation of main engine.
Yet another object of the present invention is to provide an external arrangement for regeneration of the POC that comes into action and goes out of action independent of the primary engine.
Yet another object of the present invention is to provide an external arrangement for regeneration of the POC that does not interfere with its normal operation.
SUMMARY OF INVENTION:
A regeneration system for particulate filter comprising an exhaust system, an auxiliary engine, said auxiliary engine is controlled through electronic throttle body, exhaust of said engine is connected to the exhaust system being regenerated through exhaust gas inlet pipe which is upstream of particulate filter, said exhaust system also consists of a fresh air inlet point which is located in upstream of exhaust gas inlet pipe in said exhaust system of said auxiliary engine, a thermocouple installed downstream of said particulate filter and signal from said thermocouple is given to EMS of said auxiliary engine for controlling electronic throttle body.
The mixture of air, exhaust gases is provided at ~ 600 deg C which initiates regeneration of open particulate filter. The regeneration is achieved by converting trapped particulate matter into C02 subsequently. The auxiliary engine is a fuel injected type S.I. engine. The auxiliary engine is operated through an electronic throttle body and said EMS system. The

EMS system of the gas engine receives the exhaust gas temperature after POC as an input signal. Based on said input signal throttle position is controlled. The throttle position controls the exhaust gas temperature. The partial particulate filter is installed downstream of diesel oxidation catalyst. The silencer is fitted downstream of said particulate trap.
A method of regenerating for particulate filter said method comprising acts of providing a system and an arrangement that provides an external assist for regeneration of the diesel particulate trap, providing heat of the exhaust gas of a gas engine, adding fresh air into the exhaust gas of the gas engine, passing mixture generated which is at a temperature ~ 550-600 deg C and also containing oxygen (essential for oxidation of soot) through the diesel particulate trap, oxidation of accumulated soot, monitoring and controlling the temperature of the exhaust in order to control the regeneration and damage to substrate of the particulate trap, controlling the inlet of S.I. engine exhaust temperature & fresh air quantity, operating the S.I. engine through an electronic throttle body & the EMS system, receiving input signal by the gas engine from the exhaust gas temperature to control the throttle position which in turn controls the exhaust gas temperature, connecting the auxiliary engine is o alternator which further charges the vehicle battery or any auxiliary battery, maintaining operation of auxiliary engine & the regeneration independent of the main vehicle engine.
BRIEF DESCRIPTION:
The sketches showing details of the arrangement of components for a thermostat bypass
device are given herewith
Figure 1 shows the schematic arrangement of exhaust system components constructional
details of the arrangement of components of the cooling system.
Fig 2 shows the schematic of exhaust system components in accordance with the present
invention.
Fig. 3 shows the schematic details of the electronic controller that controls the operation of
the auxiliary engine.
DETAILED DESCRIPTION:
The present invention aims at providing a system and an arrangement that provides an external assist for regeneration of the diesel particulate trap. The external assist is provided

the heat of the exhaust gas of a gas engine. Fresh air is added into the exhaust gas of a gas engine. The mixture which is at a temperature ~ 550-600 deg C and also containing oxygen (essential for oxidation of soot) is then passed through the diesel particulate trap. Since the conditions are favorable for passive regeneration, the oxidation of accumulated soot takes place. In order to control the regeneration and also the damage to the substrate of the particulate trap. The temperature of the exhaust coming out of particulate trap is monitored and controlled. This is in turn controlled through the inlet S.I. engine exhaust temperature & fresh air quantity. The S.I. engine is operated through an electronic throttle body & the EMS system of the gas engine receives the exhaust gas temperature after the POC an input signal to control the throttle position which in turn controls the exhaust gas temperature. The auxiliary engine is connected to alternator which further charges the vehicle battery or any auxiliary battery. The operation of auxiliary engine & the regeneration is independent of the main vehicle engine.
The present invention utilises air as an element that can control the process of regeneration. In addition it utilizes the heat of the exhaust gas of an auxiliary engine which otherwise goes waste. The work output of the auxiliary engine can also be used for some useful purpose.
The particulate trap is placed after the diesel oxidation catalyst and to trap particulate matter. The trapping efficiency depends upon the type of particulate trap. The open particulate traps irrespective of their type have limited storage capacity and the trapped particulate matter (primarily carbon) is subsequently required to be converted into C02 so as to ensure continuous particulate matter trapping during subsequent vehicle operation. This is called as regeneration which has a great significance from long term durability point of view. The oxidation of the particulate matter takes place by following two mechanisms -
I) During vehicle accelerations and higher vehicle speeds, DOC converts the available NO into N02 when temperatures are above 220° C. The NO - N02 conversion efficiency of the DOC depends on the exhaust gas temperatures prior to DOC. Nascent generated N02 reacts with Soot (carbon), CO (Carbon monoxide) & HC (Hydro carbon) and following reaction takes place,
N02 + C →NO + C02 N02 + CO → NO + C02 N02 +HC→ NO + C02 + H20

Thus the collected and stored Soot particles, gets burnt inside Particulate trap. Providing precious metal coating on the POC helps on site burning of the Soot.
ii) The other soot burning mechanism involves oxidation of the soot at temperatures ~ 600°C. This temperature is attained during high speed high load engine operation. At this temperature the oxygen present in the exhaust gas reacts with the carbon.
Both these mechanisms of oxidation of the soot occur within a specific band of temperature and availability of N02 species. However, during actual vehicle operation the duration of achieving these regeneration conditions depend primarily on vehicle driving conditions which are beyond control. For example, the vehicles running primarily in city or in congested traffic can not attain the exhaust temperature of - 600 deg C. This may result in insufficient regeneration. The non regenerated soot remains stored on the open particulate filter.
Thus, any other regeneration mechanism, which is independent of the base diesel engine / vehicle operation, will lead to better regeneration. The present invention aims at providing an external arrangement that provides a mixture of air, exhaust gases at ~ 600 deg C which would initiate regeneration of the open particulate filter.
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same As shown in figure 1, the exhaust system (including after treatment system comprises of) a diesel oxidation catalyst (11) and a partial particulate trap (12) which is installed downstream of the diesel oxidation catalyst. Silencer (13) is fitted downstream of the particulate trap. The entire exhaust system is mounted on the vehicle with the help if suitable hangers (14).
As shown in figure 2 the external arrangement for achieving regeneration of the particulate trap comprises of the exhaust system as explained earlier and in addition, a fuel injected type S.I. engine (21) as an auxiliary engine. The auxiliary engine is controlled through electronic throttle body (22). The exhaust of the engine is connected to the exhaust system being regenerated through exhaust gas inlet pipe (23) which is just upstream of the particulate trap. The exhaust system also comprises of a fresh air inlet point (24) which is located in the upstream of exhaust gas inlet pipe (22) in the exhaust system of auxiliary engine. A thermocouple is installed downstream of the particulate filter. The signal from the thermocouple is given to the ECU of the auxiliary engine.

Working of the system is as given below -
The particulate filter has stored sufficient amount of particulate matter and needs to be generated. The auxiliary engine is started the operating point of the auxiliary engine is such that the exhaust gas temperature is within the regeneration range of the particulate trap (typically ~ 600 deg. C) Since the auxiliary engine is a close loop spark engine, the exhaust coming out of the auxiliary engine does not contain any particulate mater and also any amount of oxygen. The fresh air added into the exhaust gas of the auxiliary engine before it is fed into the particulate trap. Thus, before entering the particulate trap (which is to be regenerated), the exhaust gas coming out of the auxiliary engine comprises of sufficient amount of oxygen that is necessary for oxidation of the particulate matter. This exhaust gas (which also contains oxygen in it) is then passed through the particulate trap. The gas temperature which is in the range of ~ 600 deg C & presence of oxygen provide favorable conditions for oxidation of the particulate trap. Thus, the particulate trap gets regenerated. Oxidation of particulate matter is an exothermic reaction. This results in increase in temperature of the gas that comes out of the particulate trap. The exhaust gas temperature at the outlet of particulate trap is monitored through a thermocouple. The temperature signal is given to the ECU of the auxiliary engine. Base on the temperature signal following two conditions can occur -
i) Temperature of the gas at the outlet of particulate trap does not increase over a
period of time.
ii) Temperature of gas at the outlet of particulate trap increases rapidly and exceeds (say 750 deg C) The first condition occurs at the beginning of the regeneration & at the end of regeneration when the exothermic oxidation reaction no more take place. This condition is used to determine the point to stop the auxiliary engine.
The second condition refers very fast oxidation reactions leading to heating up of the system & the exhaust gases.
Figure 3 shows the schematic details of input & out parameters for the Engine management system of the auxiliary engine. The ECU (31) is a typical close loop S.I. engine ECU which primarily comprises of engine management strategies (32) for air fuel ratio & spark control. In addition, it receives the temperature input from thermocouple (33) which is installed at

the outlet of the particulate trap. The controller monitors the temperature and based on the temperature signal over period of time it takes the following decisions (34)-
i) Stops the engine if the temperature starts rising continuously and provides an
alarm for system overheat.
ii) Gives an indication of completion of regeneration.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:
1. A regeneration system for particulate filter comprising:
an exhaust system, an auxiliary engine, said auxiliary engine is controlled through
electronic throttle body,
exhaust of said engine is connected to the exhaust system being regenerated through
exhaust gas inlet pipe which is upstream of particulate filter,
said exhaust system also consists of a fresh air inlet point which is located in upstream of
exhaust gas inlet pipe in said exhaust system of said auxiliary engine
a thermocouple installed downstream of said particulate filter and signal from said
thermocouple is given to EMS of said auxiliary engine for controlling electronic throttle
body.
2. The regeneration system for particulate filter as claimed in claim 1 wherein, a mixture of
air, exhaust gases is provided at ~ 600 deg C which initiates regeneration of open
particulate filter.
3. The regeneration system for particulate filter as claimed in claim 1 wherein, said
regeneration is achieved by converting trapped particulate matter into C02 subsequently.
4. The regeneration system for particulate filter as claimed in claim 1 wherein, said auxiliary
engine is a fuel injected type S.l. engine.
5. The regeneration system for particulate filter as claimed in claim 1 wherein, said auxiliary.engine is operated through an electronic throttle body and said EMS system.
6. The regeneration system for particulate filter as claimed in claim 1 wherein, said EMS system of the gas engine receives the exhaust gas temperature after POC as an input signal.
7. The regeneration system for particulate filter as claimed in claim 1 wherein, based on said input signal throttle position is controlled.
8. The regeneration system for particulate filter as claimed in claim 1 wherein, said throttle position controls the exhaust gas temperature

9. The regeneration system for particulate filter as claimed in claim 1 wherein, said partial
particulate filter is installed downstream of diesel oxidation catalyst.
10. The regeneration system for particulate filter as claimed in claim 1 wherein, a silencer is fitted downstream of said particulate trap.
11. A method of regenerating for particulate filter said method comprising acts of:

- providing a system and an arrangement that provides an external assist for regeneration of the diesel particulate trap,
- providing heat of the exhaust gas of a gas engine,
- adding fresh air into the exhaust gas of the gas engine,
- passing mixture generated which is at a temperature ~ 550-600 deg C and also containing oxygen (essential for oxidation of soot) through the diesel particulate trap
- oxidation of accumulated soot,
monitoring and controlling the temperature of the exhaust in order to control the regeneration and damage to substrate of the particulate trap,
- controlling the inlet of S.I. engine exhaust temperature & fresh air quantity
- operating the S.I. engine through an electronic throttle body & the EMS system,
- receiving input signal by the gas engine from the exhaust gas temperature to control the throttle position which in turn controls the exhaust gas temperature
-connecting the auxiliary engine is o alternator which further charges the vehicle battery or any auxiliary battery,
- maintaining operation of auxiliary engine & the regeneration independent of the main vehicle
engine.
12. A regeneration system for particulate filter as herein described with reference to accompanying drawings.